[time-nuts] 10811 Alternatives

Bob Camp kb8tq at n1k.org
Mon Apr 13 07:53:38 EDT 2015


Hi

I probably should not rule out the MV89’s going through an exceptionally brutal 
salvage process. I’m sure there are a range of outfits doing this stuff and that 
some take more care than others. We may just have a lot of 10,000 MV-89’s 
that got nuked and now are forever floating around the world getting re-sold multiple 
times.

You could ask - why not test them fully? That’s not an easy task. The list I gave is
far from a full test process on an OCXO. One would at least add aging and some 
more detailed limits here and there to a proper test profile. If you are looking for 
damaged parts, there would be even more testing required past a normal testing profile. 
I’ve always found that building in performance / reliability  is a lot cheaper than testing it in …..

Bob

> On Apr 12, 2015, at 10:03 PM, Peter Bell <bell.peter at gmail.com> wrote:
> 
> I would personally consider those MV89s from Chinese sources as being extra
> suspect - a few years back, one of the Chinese surplus vendors had a big
> box of them (some removed from PCBs, and others apparently new) that were
> identified to me as containing bad ceramic caps and suffering from various
> problems ranging from poor phase noise performance to being completely
> inoperative.
> 
> The guy who had them (who I know quite well) volunteered this information
> and said that as far as he was concerned they could only be sold as scrap -
> but it's possible they have ended up in the hands of dealers that are not
> so scrupulous.
> 
> 
> On Mon, Apr 13, 2015 at 8:46 AM, Bob Camp <kb8tq at n1k.org> wrote:
> 
>> Hi
>> 
>> I don’t think there’s anything at all wrong with the MV-89A as an OCXO. In
>> fact, I believe that properly
>> handled they are a good part. The gotcha is the abuse they get in the
>> “recycling” process. I’m
>> willing to bet that any OCXO that sees the same sort of process will come
>> out with issues.
>> 
>> Bottom line - Don’t attack an OCXO with a torch, drop it down a flight of
>> stairs, leave it out in the rain
>> for a few years, and then really abuse it after that. They need to be
>> treated with some care ….
>> 
>> For what ever reason, parts like IC’s seem to be more tolerant of the
>> scrap out process than OCXO’s.
>> Rb’s seen to show up *with* PCB’s still attached, so they didn’t get the
>> torch process.
>> 
>> Because of all that, there’s not much way to pick a “good” OCXO model. The
>> thing you need to find
>> are parts that you are sure did not take a beating while being pulled off
>> of boards. With zero view into
>> that end of the sourcing process …. not much way to pick and choose.
>> 
>> About the only thing to do is to buy parts that never went on to pc
>> boards. That’s no guarantee, but
>> it ups the odds a bit. You may be buying test rejects. They could still
>> have been dropped down a
>> flight of stairs. They might be counterfeit parts.
>> 
>> Considering that you are buying a $250 to $400 OCXO for <$20, there *will*
>> always be some risk ….
>> 
>> Bob
>> 
>>> On Apr 12, 2015, at 6:02 PM, Perry Sandeen via time-nuts <
>> time-nuts at febo.com> wrote:
>>> 
>>> List,
>>> 
>>> 
>>> 
>>> It appears from Bob Camp’sexperience (and others) that the Chicoms
>> Morion oscillators are to be avoided.
>>> 
>>> 
>>> 
>>> My question is: Could Bob Camp,Rick K. and other gurus with experience
>> come up with a list of the Ebay 10 MHzsurplus oscillators that would be
>> worth buying as well as what would be a fairprice? Also some good vendor
>> names would be nice as well.
>>> 
>>> 
>>> 
>>> I realize that surplus listvaries quite a bit and it still a bit of a
>> crap shoot, but perhaps the odds arebetter from certain venders, makes, and
>> models.
>>> 
>>> 
>>> 
>>> Regards,
>>> 
>>> 
>>> 
>>> Perrier
>>> 
>>> 
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